Class-specific attention module computes the attention weight \(a[c,t]\)  (def REF ) for all action classes \(c\)  and all temporal positions \(t\)  in each video. The attention scores attend to the portions of the video where an activity of a certain category occurs. Therefore, video segments with attention scores higher than a threshold are localized as action parts. Class-specific attention module is used in [1]}, [2]}, [3]}, [4]} to localize the temporal boundary of action instances.
